In order to speed up chemical testing procedures there is an increasing demand for making manifold analyses in parallel. In typical cases such parallel analyses are performed in an array of separate test tubes or in different wells of a single unit called a microtitre plate.
A problem with such an approach arises during incubation, that is, when the samples are heated or cooled to desired reaction temperatures, which use to be referred to as “well-to-well uniformity”. The problem is to expose the separate tubes or wells uniformly for the heating and cooling medium, often a gas or a liquid and to obtain homogeneous temperature within this medium.
The major source of poor thermal uniformity is the temperature gradients commonly established from the edges to the center of the tube array or the microtitre plate. Such gradients are more severe if the tubes or wells are obstacles for the flow of the medium, which often is the case.